Ligaments are tough bands of tissue which serve to connect the articular extremities of bones, or to support or retain organs in place within the body. Ligaments are typically composed of coarse bundles of dense white fibrous tissue which are disposed in a parallel or closely interlaced manner, with the fibrous tissue being pliant and flexible, but not significantly extensible.
In many cases, ligaments are torn or ruptured as a result of accidents or overexertion. Accordingly, various procedures have been developed to repair or replace such damaged ligaments. For example, in the human knee, the anterior and posterior cruciate ligaments (i.e., the ACL and PCL) extend between the top end of the tibia and the bottom end of the femur. The ACL and PCL cooperate, together with other ligaments and soft tissue, to provide both static and dynamic stability to the knee. Often, the ACL is ruptured or torn as a result of, for example, a sports-related injury. Consequently, various surgical procedures have been developed for reconstructing the ACL so as to restore normal function to the knee.
In many instances, the ACL may be reconstructed by replacing the ruptured ACL with a graft ligament. More particularly, with such procedures, bone tunnels are typically formed in the top end of the tibia and the bottom end of the femur, and one end of the graft ligament is positioned in the femoral bone tunnel and the other end of the graft ligament is positioned in the tibial bone tunnel. The graft ligament thus extends between the femur and the tibia in substantially the same way, and with substantially the same function, as the original ACL, thereby allowing the graft ligament to cooperate with the surrounding anatomical structures so as to restore normal function to the knee.
When anchoring a graft ligament to the tibia and the femur, the two ends of the graft ligament are typically attached to an anchoring member, such as a bone plug, that is inserted into a bone tunnel. Bone screws or similar fasteners are often used to maintain each bone plug within its respective tunnel. Such a procedure typically requires a recess to be formed in the bone adjacent to the bone tunnel to allow the bone screw to be inserted alongside the bone plug. The recess serves as a “starter hole” for the bone screw so that the screw can engage bone in a generally proper direction with respect to the bone tunnel. As the bone screw is threaded into the bone, the resulting interference fit between the bone plug and the bone screw secures the graft ligament in place in the bone tunnel.
Since ACL repair is typically performed arthroscopically, the current procedure for forming a bone recess requires the surgeon to estimate the best location for positioning the bone screw adjacent to the bone plug. In particular, current devices for forming a recess in a bone tunnel have a relatively large size that requires that the recess be formed before the bone plug is inserted into the tunnel, thus the surgeon cannot determine the best location for the recess, and consequently for the bone screw, in relation to the bone plug. Once the recess is formed, a guidewire must be positioned between the anchoring member and a sidewall of the bone tunnel for delivering a bone screw to the tunnel at a location adjacent to the recess. Since the guidewire is delivered after formation of the notch, the position of the guidewire is often estimated as well. Accordingly, these methods and devices can result in misalignment of the bone screw, thus resulting in a high rate of divergence between the bone screw and the bone tunnel, and often in a loss of bone plug fixation within the bone tunnel. Unfortunately, screw/tunnel divergence is usually only identified postoperatively via radiographs, and the loss of bone plug fixation cannot be readily corrected, thereby resulting in an unsuccessful repair of a ruptured ACL.
Thus, there remains a need for improved methods and devices for creating a notch and positioning a guidewire within a bone tunnel to provide an accurate, secure, and trouble-free fixation of a ligament within the bone tunnel.